JP2006202371A - Manufacturing method of master disk for perpendicular magnetic transfer and perpendicular magnetic transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a master disk for perpendicular magnetic transfer which can perform successful magnetic transfer to a perpendicular magnetic recording medium and a perpendicular magnetic transfer method using this master disk. <P>SOLUTION: A substrate 47 on whose surface a number of fine projection pattern 47A are formed is applied with a resist agent R, the surface of the projection pattern is covered with the resist agent, and a concave section 47B is almost filled with the resist agent. While removing completely the resist agent which covers the surface of the projection pattern by ashing, a part of the resist agent almost filled the concave section is removed. A magnetic film is formed on the surface of the substrate, and a magnetic layers 48 are formed on the surface of the projected pattern from where the resist agent is removed and the concave section from where a part of the resist agent is removed. The resist agent applied to the concave section is removed, and lift-off to remove selectively the magnetic layer of the concave section is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a master disk for perpendicular magnetic transfer and a perpendicular magnetic transfer method, and particularly suitable for perpendicular magnetic transfer of a magnetic information pattern such as format information to a magnetic disk used in a hard disk device or the like. The present invention relates to a method for manufacturing a magnetic transfer master disk, and a perpendicular magnetic transfer method using the perpendicular magnetic transfer master disk.

  In recent years, magnetic disks (hard disks) used in hard disk drives, which have been rapidly spreading, are written with format information and address information before being installed in the drive after being delivered to the drive manufacturer by the magnetic disk manufacturer. It is common. Although this writing can be performed by a magnetic head, a method of batch transfer from a master disk in which these format information and address information are written is efficient and preferable.

  This magnetic transfer technology applies a magnetic field for transfer by arranging magnetic field generating means such as an electromagnet device or a permanent magnet device on one side or both sides in a state where a master disk and a disk to be transferred (slave disk) are in close contact with each other. The magnetic pattern corresponding to the information (for example, servo signal) of the master disk is transferred.

  For such magnetic transfer, various configurations and methods have been conventionally proposed (for example, Patent Documents 1 and 2). In the proposal of Patent Document 1, a master disk is held by a pair of holder units, a slave disk is supplied between a pair of master disks by a robot hand, and then transferred while being held in pressure contact with both sides of the slave disk. The present invention relates to a device that applies a magnetic field for operation.

  The proposal of Patent Document 2 is a method of applying a magnetic field for transfer while pressing a master disk, in which a concave and convex shape corresponding to an information signal is formed on a surface of a substrate and at least a convex surface is made of a ferromagnetic material, in pressure contact with a slave disk. It is about.

  By the way, the magnetic recording medium is classified into an in-plane magnetic recording medium having an easy axis in the plane of the magnetic layer and a perpendicular magnetic recording medium having an easy axis in the direction perpendicular to the plane of the magnetic layer. However, conventionally, an in-plane magnetic recording medium has been generally used.

  On the other hand, the development of perpendicular magnetic recording media and perpendicular magnetic recording methods that can be expected to greatly improve recording density (increasing storage capacity) is underway, and in the near future, large-scale introduction to the market is screaming. It has been released.

Therefore, the above-described magnetic transfer is also required to have a configuration corresponding to perpendicular magnetic recording. That is, the development of the above-described magnetic transfer technology is proceeding mainly with respect to magnetic transfer to an in-plane magnetic recording medium, and development of a magnetic transfer technology applicable to perpendicular magnetic recording is required.
JP 2004-87099 A JP 10-40544 A

  However, when performing magnetic transfer to a perpendicular magnetic recording medium, it is necessary to apply a magnetic field in a direction perpendicular to the surface of the magnetic layer, which requires different conditions from the in-plane magnetic recording medium, and has inherent problems. Have

  For example, at the time of magnetic transfer to a perpendicular magnetic recording medium, there is a problem that the magnetization disturbance is large at the boundary between the magnetization reversal part and the magnetization non-reversal part, and the signal quality is not good. This problem is caused by insufficient convergence of the magnetic flux toward the magnetization reversal part, and it has become clear from the analysis by the present inventors that it causes a reduction in signal quality.

  Also, in perpendicular magnetic transfer, the thickness of the convex pattern by the magnetic layer of the master disk is thin, the magnetic pole distance generated because the magnetic field passes perpendicularly through this magnetic layer, and the magnetic flux between adjacent convex parts For example, it is difficult to realize a sufficient signal quality simply by forming a magnetic layer having a simple shape because there is no assist for converging the light to the convex portion.

  The present invention has been made in view of such circumstances, and a method for manufacturing a perpendicular magnetic transfer master disk capable of performing good magnetic transfer on a perpendicular magnetic recording medium, and the perpendicular magnetic transfer master disk It is an object of the present invention to provide a perpendicular magnetic transfer method using

  In order to achieve the above object, the present invention applies a resist agent to a disk-shaped substrate having a number of fine protrusion patterns formed on the surface, covers the surface of the protrusion pattern with the resist agent, The resist coating step of substantially filling the concave portion formed between the protruding patterns with the resist agent and the resist agent covering the surface of the protruding pattern are completely removed by ashing, and the concave portion is removed. A resist removing step of removing a part of the resist agent substantially filled in the part, a magnetic film is formed on the surface of the substrate, the surface of the protruding pattern from which the resist agent is removed, and the resist agent A magnetic layer forming step of forming a magnetic layer in the removed concave portion, and the resist agent applied to the concave portion is removed, and the magnetic layer in the concave portion is selectively removed. And Futoofu step, to provide a method of manufacturing a perpendicular magnetic transfer master disk, characterized in that it comprises a.

  According to the method of the present invention, a resist agent is applied to the substrate and the surface of the protruding pattern is covered with the resist agent, and the resist agent is substantially filled in the recessed portion, and then the surface of the protruding pattern is covered by ashing. The resist agent is completely removed, and a part of the resist agent substantially filled in the recessed portion is removed.

  That is, since the thickness of the resist agent covering the surface of the projection pattern is different from the thickness of the resist agent filled in the recess portion, the recess portion is completely removed when the resist agent covering the surface of the projection pattern is completely removed. The resist agent filled in remains, and covers the bottom surface of the recess. Next, a magnetic film is formed on the surface of the substrate, and a magnetic layer is formed on the surface of the protruding pattern from which the resist agent has been completely removed and on the surface of the resist agent remaining in the recess.

  Thereafter, if the resist agent in the recess is removed, the magnetic layer on the surface of the resist agent is also removed at the same time, and a perpendicular magnetic transfer master disk in which the magnetic layer is formed only on the surface of the protruding pattern is obtained. That is, a lift-off process for selectively removing the magnetic layer in the recessed portion is performed.

  According to the master disk for perpendicular magnetic transfer according to the method of the present invention, since the magnetic layer is formed only on the surface of the protruding pattern, there is no defect, magnetic transfer can be performed with good accuracy, and the C / N ratio is good. A perpendicular magnetic recording medium (slave disk) can be obtained.

  A further advantage of the method according to the invention is that this duplicate can be easily manufactured after the master disk has been manufactured. Various methods are conceivable for manufacturing a master disk in which a concavo-convex shape corresponding to an information signal is formed on the surface of a flat substrate and the surface of the convex portion is made of a ferromagnetic material (for example, Patent Document 2). However, in the method of Patent Document 2, a concavo-convex shape is formed after the magnetic layer is formed on substantially the entire surface of the substrate, and this configuration cannot produce a duplicate.

  After the drawing process that takes the most time when manufacturing the master disk (irradiating a laser beam (or electron beam) modulated in accordance with the servo signal and exposing the substantially entire surface of the photoresist layer), the duplicate is produced. If it cannot be manufactured, the unit price of the master disk will be very high.

  As described above, the present invention provides a method capable of producing a duplicate of a master disk having a magnetic layer only on a convex portion after the drawing process, which has not been conventionally seen.

  In the present invention, the ratio t / l between the thickness t of the magnetic layer and the radial width l of the protruding pattern is preferably 1 or more. By using the ratio of the thickness t of the magnetic layer to the radial width l of the protrusion pattern, the magnetization direction of the magnetic layer can be stably maintained perpendicular to the disk surface, and the master for perpendicular magnetic transfer. Preferred as a disk.

  In the present invention, the ratio t / b between the thickness t of the magnetic layer and the circumferential width b of the protruding pattern is preferably 1 or more. By using the ratio of the thickness t of the magnetic layer to the circumferential width b of the protrusion pattern, the magnetization direction of the magnetic layer can be stably maintained perpendicular to the disk surface, and the magnetic layer can be used for perpendicular magnetic transfer. Preferred as a master disk.

  Thus, it is presumed that the reason why the ratio t / l and the ratio t / b are preferably 1 or more is related to a phenomenon in which a demagnetizing field is generated by applying a magnetic field during magnetic transfer.

  Further, in the present invention, a large number of fine projection patterns and concave portions formed between the projection patterns are alternately formed on the surface, and a magnetic layer is formed on the surface of the projection pattern. And a magnetic field generating means for applying a magnetic field in a direction perpendicular to the surfaces of the disk to be transferred and the master disk, and a magnetic pattern of the master disk is formed. A perpendicular magnetic transfer method comprising: a magnetic transfer step of transferring to the transfer target disk.

  According to the method of the present invention, since the magnetic layer is formed only on the surface of the protruding pattern, there is no other portion of the magnetic layer that becomes a disturbance during transfer, there is no defect, and magnetic transfer can be performed with good accuracy. Thus, a perpendicular magnetic recording medium (slave disk) having a good C / N ratio can be obtained.

  In the present invention, it is preferable to perform magnetic transfer while relatively moving the disk to be transferred and the master disk in close contact with the magnetic field generating means. Thus, the magnetic transfer efficiency is improved by relatively moving the magnetic field generating means and the magnetic medium.

  As described above, according to the present invention, since the magnetic layer is formed only on the surface of the projection pattern of the master disk, there is no defect, magnetic transfer can be performed with good accuracy, and the C / N ratio is good. A perpendicular magnetic recording medium (slave disk) can be obtained.

  Hereinafter, preferred embodiments of a method for manufacturing a master disk for perpendicular magnetic transfer and a perpendicular magnetic transfer method according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view of a master disk according to the present invention. FIG. 2 is a partially enlarged perspective view showing a fine protrusion pattern on the surface of the master disk 46. Note that FIG. 2 is a schematic diagram, and the dimensions of each part are shown in proportions different from actual ones.

  As shown in FIG. 1, the master disk 46 is formed in a disk shape, and a radially inner peripheral portion of the master disk 46 (a portion excluding the inner peripheral portion 46 d and the outer peripheral portion 46 e of the master disk 46) Servo regions 46b and non-servo regions 46c (non-hatched portions) indicated by hatching are alternately formed in the circumferential direction.

  The servo area 46b is an area where a magnetic pattern (servo information pattern) is formed, and the non-servo area 46c is an area where a magnetic pattern (servo information pattern) is not formed.

  The master disk 46 has an annular shape (doughnut shape) having an inner diameter, but may be a disk shape having no inner diameter.

  FIG. 2 is a partially enlarged view of the servo area 46b. A transfer information carrying surface on which a fine projection pattern is formed by the magnetic layer 48 is formed on one surface of the substrate 47, and the surface on the opposite side of the substrate 47 is It is held by close contact means (not shown). The fine protrusion pattern is formed by a photofabrication method to be described later. One surface (transfer information carrying surface) of the master disk 46 is a surface in close contact with the slave disk 40.

  The fine protrusion pattern is rectangular in plan view, and in the state where the magnetic layer 48 having a thickness t is formed, the length b in the track direction (thick arrow direction in the figure) and the length l in the radial direction. And more. The optimum values of the lengths b and l vary depending on the recording density, the recording signal waveform, and the like. For example, the length b can be 80 nm and the length l can be 200 nm.

  In the case of a servo signal, this fine projection pattern is formed long in the radial direction. In this case, for example, the length l in the radial direction is preferably 0.05 to 20 μm, and the length b in the track direction (circumferential direction) is preferably 0.05 to 5 μm. It is preferable to select a pattern having a longer radial direction within this range as a pattern carrying servo signal information.

  The depth of the fine protrusion pattern (projection height) on the surface of the substrate 27 is preferably in the range of 80 to 800 nm, and more preferably in the range of 100 to 600 nm.

  In the master disk 46, when the substrate 47 is a ferromagnetic material mainly composed of Ni or the like, magnetic transfer can be performed only by the substrate 47, and the magnetic layer 48 may not be covered, but the transfer characteristics are good. By providing the magnetic layer 48, better magnetic transfer can be performed. When the substrate 47 is a nonmagnetic material, it is necessary to provide the magnetic layer 48. The magnetic layer 48 of the master disk 46 is preferably a soft magnetic layer having a coercive force Hc of 48 kA / m (≈600 Oe) or less.

  As the substrate 47 of the master disk 46, glass of various compositions such as nickel, silicon, quartz glass, aluminum, alloys, ceramics of various compositions, synthetic resins, and the like can be used. However, in the case of a synthetic resin, it is necessary to use a material that does not change with a resist stripping solution in a lift-off process, which will be described later, or a device that does not change with a resist stripping solution (for example, a protective coat).

  The uneven pattern on the surface of the substrate 47 can be formed by a photofabrication method, a stamper method using a master disk formed by a photofabrication method, or the like.

  Formation of the master in the stamper method can be performed, for example, as follows. A photoresist layer is formed on a glass plate (or quartz glass plate) having a smooth surface by spin coating or the like, and after pre-baking, the laser plate is rotated in response to a servo signal while rotating the glass plate ( Or a portion corresponding to each frame on the circumference of a predetermined pattern, for example, a pattern corresponding to a servo signal extending linearly in the radial direction from the center of rotation to each track. To expose.

  Thereafter, the photoresist layer is developed to obtain a glass master having a concavo-convex shape formed by the photoresist layer from which the exposed portion has been removed. Next, based on the concavo-convex pattern on the surface of the glass master, the surface is plated (electroformed) to form a predetermined thickness, thereby creating a Ni substrate having a positive concavo-convex pattern on the surface. Then, the substrate is peeled from the glass master.

  This substrate is used as a press master as it is, or a soft master layer, a protective film, etc. are coated on the concavo-convex pattern as necessary to form a press master.

  Alternatively, the glass master may be plated to create a second master by electroforming, and the second master may be further plated to create a reversing master having a negative uneven pattern by electroforming. . Furthermore, the second master is plated and electroformed, or a low-viscosity resin is pressed and cured to create a third master, and the third master is plated and electroformed. A substrate having a positive uneven pattern may be formed.

  On the other hand, the master can be formed in the photofabrication method as follows, for example. A photoresist layer is formed on the flat surface of a flat substrate by spin coating, etc. After pre-baking, the substrate is rotated and irradiated with laser light (or electron beam) modulated in response to the servo signal. A predetermined pattern, for example, a pattern corresponding to a servo signal extending linearly from the center of rotation to each track in a radial direction is exposed on the entire surface of the photoresist layer in a portion corresponding to each frame on the circumference.

  Thereafter, the photoresist layer is developed to obtain a substrate having a concavo-convex shape formed by the photoresist layer from which the exposed portion has been removed. The substrate after the development process is post-baked to increase the adhesion of the photoresist layer to the substrate.

  Next, the substrate is etched by an etching process to form holes having a depth corresponding to the concavo-convex pattern. Next, the photoresist is removed, the surface is polished, and if there are burrs, they are removed and the surface is smoothed. Thereby, a master having an uneven shape is obtained.

  Next, based on the concavo-convex pattern on the surface of the master, the surface is plated (electroformed) to form a predetermined thickness, thereby creating a Ni substrate having a negative concavo-convex pattern on the surface. Then, the substrate is peeled from the master.

  As the material of the substrate or the master by electroforming, Ni or Ni alloy can be used as the metal. As a plating method for producing this substrate, various metal film forming methods including electroless plating, electroforming, sputtering, and ion plating can be applied.

  Next, a method for forming the magnetic layer 48 will be described. FIG. 3 is a cross-sectional view of the substrate 47 for explaining the flow of forming the magnetic layer 48. FIG. 3A shows an unprocessed substrate 47, which is formed on the surface of the substrate 47 by the above-described steps between a large number of fine protrusion patterns 47A, 47A, and the protrusion patterns 47A, 47A. The recessed portions 47B, 47B... Are alternately formed.

  First, as shown in FIG. 3B, a resist agent R is applied to the surface of the substrate 47, and the resist agent R covers the surfaces of the protruding patterns 47A, 47A. 47B is substantially filled. As the resist agent R, a photoresist is generally used, but it is not limited to a photoresist as long as it can perform a lift-off process to be described later, and various other materials can be used.

  As a method for applying the resist agent R, various known methods such as spin coating, die coating, roll coating, dip coating, screen printing, and the like can be employed. If the size of the recessed portions 47B, 47B... Is very small, it may be difficult to substantially fill the recessed portions 47B, 47B... With a resist agent R having a predetermined viscosity or more. What is necessary is just to reduce the viscosity of the resist agent R by the above.

  Also, there is a method in which the resist 47 is applied to the surface of the substrate 47 and then released to atmospheric pressure in a reduced pressure atmosphere (for example, the substrate 47 is put in a desiccator and the desiccator is evacuated by a rotary vacuum pump or the like). It is effective for filling the resist agent R into the concave portions 47B, 47B.

  Similarly, for example, a method in which the substrate 47 is placed in a desiccator, the resist agent R is applied to the surface of the substrate 47 in a state where the atmospheric pressure is released, and then the inside of the desiccator is evacuated by a rotary vacuum pump or the like is also a micro size It is effective to fill the concave portions 47B, 47B. In this case, by evacuation, bubbles are generated in the resist agent R from the recessed portions 47B, 47B... And disappear from the surface of the resist agent R.

  Next, the resist agent R is cured in the state of FIG. When the resist agent R is a negative type photoresist (for example, a cyclized rubber type), it may be crosslinked by irradiation with ultraviolet rays or the like. In the case where the resist agent R is a positive type photoresist, a baking treatment (post-bake) may be performed for crosslinking polymerization.

  Next, as shown in FIG. 3C, the resist agent R covering the surface of the protruding patterns 47A, 47A,... Is completely removed by ashing, and the resist substantially filled in the recesses 47B, 47B,. Part of the agent R is removed.

  That is, since the thickness of the resist agent R that covers the surface of the protrusion patterns 47A, 47A, and the thickness of the resist agent R filled in the recesses 47B, 47B, ... are different, the surface of the protrusion patterns 47A, 47A,. When the covered resist agent R is completely removed, the resist agent R filled in the recessed portions 47B, 47B... Remains and covers the bottom surfaces of the recessed portions 47B, 47B.

  Next, as shown in FIG. 3D, a magnetic film is formed on the surface of the substrate 47, and the surfaces of the protruding patterns 47A, 47A ... from which the resist R has been completely removed, and the recessed portions 47B, 47B ... A magnetic layer 48 is formed on the surface of the resist agent R remaining therein.

  The magnetic layer 48 (soft magnetic layer) is formed by depositing a magnetic material by a vacuum film forming means such as a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like. As a magnetic material of the magnetic layer 48, Co, Co alloy (CoNi, CoNiZr, CoNbTaZr, etc.), Fe, Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi, FeAl, FeTaN), Ni, Ni alloy (NiFe) should be used. Can do. In particular, FeCo and FeCoNi can be preferably used.

  The thickness t of the magnetic layer 48 is preferably in the range of 50 nm to 10000 nm, and more preferably in the range of 100 nm to 5000 nm. That is, the ratio t / b between the thickness t of the magnetic layer 48 and the width of the protruding pattern (in this case, the length b in the track direction in FIG. 2) is preferably 1 or more. By setting the ratio of the thickness t of the magnetic layer 48 to the width b of the protruding pattern, the magnetization direction of the magnetic layer 48 can be stably maintained perpendicular to the disk surface, and the master for perpendicular magnetic transfer. Preferred as disk 46.

  A protective film such as diamond-like carbon is preferably provided on the magnetic layer 48, and a lubricant layer may be further provided on the protective film. In this case, the protective film is preferably a diamond-like carbon film having a thickness of 5 to 30 nm and a lubricant layer. Further, an adhesion strengthening layer such as Si may be provided between the magnetic layer 48 and the protective film. The lubricant has an effect of improving the deterioration of durability such as the occurrence of scratches due to friction when correcting the deviation caused in the contact process with the slave disk 40.

  Next, the resist agent R in the recessed portions 47B, 47B... Is removed. As a result, the magnetic layer 48 on the surface of the resist agent R is also removed. As a result, as shown in FIG. 3E, the perpendicular magnetic material in which the magnetic layer 48 is formed only on the surfaces of the protruding patterns 47A, 47A. A master disk 46 for transfer is obtained. That is, a lift-off process for selectively removing the magnetic layer 48 of the recessed portions 47B, 47B.

  As a method for removing the resist agent R in the recessed portions 47B, 47B..., When the resist agent R is a photoresist, a dedicated stripping solution is generally used. In this case, since the surface of the resist agent R is covered with the magnetic layer 48, it seems that the stripping solution does not easily act on the resist agent R, but in reality, the stripping solution penetrates through pinholes or the like of the magnetic layer 48. Acts on the resist agent R.

  Further, in order to promote the action of the stripping solution, a method of applying ultrasonic vibration or performing temperature control (heating) of the stripping solution can be preferably employed.

Further, it is possible to employ a method in which the resist agent R is decomposed by baking by leaving it in a heating atmosphere (for example, an oven) that does not alter the magnetic layer 48 for a predetermined time without using a stripping solution. This is because the photoresist is an organic substance, and is lost as CO ₂ and H ₂ O when left in a heated atmosphere (for example, an oxygen-containing atmosphere of hundreds of degrees Celsius).

  Next, a magnetic transfer method for transferring the magnetic layer pattern of the master disk 46 to the slave disk 40, which is a transfer target disk, will be described. FIG. 4 is a front view of an essential part of the magnetic transfer apparatus 10 for performing magnetic transfer using the master disk 46 according to the present invention.

  In the magnetic transfer device 10, during magnetic transfer, the slave surface (magnetic recording surface) of the slave disk 40 after initial DC magnetization described later shown in FIG. 5A is used as the information carrying surface of the master disk 46. They can be brought into contact with each other with a predetermined pressing force. Then, with the slave disk 40 and the master disk 46 in close contact with each other, a magnetic field for transfer can be applied by the magnetic field generating means 30 to transfer and record a magnetic pattern such as a servo signal.

  Next, the slave disk 40 will be described. The slave disk 40 is a disk-shaped magnetic recording medium such as a hard disk or a flexible disk having a magnetic recording layer formed on both sides or one side. Or the cleaning process (burnishing etc.) which removes adhering dust is given as needed. The slave disk 40 is preliminarily magnetized in advance. Details of this will be described later.

  As the slave disk 40, a disk-shaped magnetic recording medium such as a hard disk or a high-density flexible disk can be used. As the magnetic recording layer of the slave disk 40, a coating type magnetic recording layer, a plating type magnetic recording layer, or a metal thin film type magnetic recording layer can be adopted.

  As the magnetic material of the metal thin film type magnetic recording layer, Co, Co alloy (CoPtCr, CoCr, CoPtCrTa, CoPtCrNbTa, CoCrB, CoNi, etc.), Fe, Fe alloy (FeCo, FePt, FeCoNi) can be used. These are preferable because clear transfer can be performed because of high magnetic flux density and magnetic anisotropy in the same direction as the magnetic field application direction (perpendicular direction in the case of perpendicular magnetic recording).

  In order to provide the necessary magnetic anisotropy under the magnetic material (on the support side), it is preferable to provide a nonmagnetic underlayer. For this underlayer, it is necessary to match the crystal structure and lattice constant to the magnetic layer. For this purpose, it is preferable to use Ti, Cr, CrTi, CoCr, CrTa, CrMo, NiAl, Ru, Pd, or the like.

  Further, in order to stabilize the perpendicular magnetization state of the magnetic recording layer and improve the sensitivity during recording and reproduction, it is preferable to provide a backing layer made of a soft magnetic layer under the nonmagnetic underlayer.

  The thickness of the magnetic recording layer is preferably 10 nm to 500 nm, and more preferably 20 nm to 200 nm. Further, the thickness of the nonmagnetic layer is preferably 10 nm to 150 nm, and more preferably 20 nm to 80 nm. The thickness of the backing layer is preferably 50 nm to 2000 nm, and more preferably 80 nm to 400 nm.

  As shown in FIG. 4, the magnetic transfer by the master disk 46 includes a case where the master disk 46 is brought into close contact with one side of the slave disk 40 and sequential transfer is performed on one side, and a case where the master disks 46 and 46 are respectively applied to both sides of the slave disk 40. May be used for simultaneous transfer on both sides. The master disk 46 is subjected to a cleaning process to remove the adhering dust as needed before being brought into close contact with the slave disk 40.

  The magnetic field generating means 30 for applying the transfer magnetic field has an electromagnet device 34 in which a coil 33 is wound around a core 32 having a gap 31 extending in the radial direction of the slave disk 40 and the master disk 46 held by the close contact means arranged on the upper side. Thus, a transfer magnetic field having magnetic force lines G perpendicular to the track direction can be applied.

  When a magnetic field is applied, a transfer magnetic field is applied by the magnetic field generating means 30 while rotating the slave disk 40 and the master disk 46 together so that the transfer information of the master disk 46 can be magnetically transferred and recorded on the slave surface of the slave disk 40. The rotating means is provided. In addition to this configuration, a configuration in which the magnetic field generation unit 30 is provided to be rotationally moved can be employed.

  FIG. 5 is a cross-sectional view for explaining the basic process of magnetic transfer. 5A shows a process of applying a magnetic field in one direction to perform initial DC magnetization of the slave disk 40, and FIG. 5B shows an initial DC magnetic field obtained by bringing the master disk 46 and the slave disk 40 into close contact with each other. The process of applying a magnetic field in the opposite direction is shown, and (C) shows the state after magnetic transfer. For the slave disk 40, only the lower magnetic recording layer 40B is shown. Each figure is a schematic diagram, and the dimensions of each part are shown in proportions different from actual ones.

  As shown in FIG. 5A, an initial direct current magnetic field Hin is applied in advance to the slave disk 40 in one direction perpendicular to the track surface so that the magnetization of the magnetic recording layer 40B is initially direct current magnetized. 5B, the surface on the magnetic recording layer 40B side of the slave disk 40 and the surface on the magnetic layer 48 side of the surface of the master disk 46 are brought into close contact with each other and perpendicular to the track surface of the slave disk 40. Magnetic transfer is performed by applying a transfer magnetic field Hdu in the opposite direction to the initial DC magnetic field Hin.

  As a result, as shown in FIG. 5C, information (for example, servo signals) corresponding to the protrusion patterns 47A, 47A,... Of the master disk 46 is magnetically transferred and recorded on the magnetic recording layer 40B of the slave disk 40. Is done.

  In the description of FIG. 5, the magnetic transfer by the lower master disk 46 to the lower magnetic recording layer 40B of the slave disk 40 has been described. The master disk 46 can be brought into close contact with the upper side, and magnetic transfer can be performed simultaneously with the lower magnetic recording layer in the same manner as the lower magnetic recording layer.

  Further, even if the concave / convex pattern (projection pattern 47A and concave portion 47B) of the master disk 46 is a negative pattern having a concave / convex shape opposite to the positive pattern in FIG. 5, the direction of the initial magnetic field Hin and the transfer magnetic field Hdu. By making the direction in the direction opposite to the above, the same information can be magnetically transferred and recorded.

  Note that the initial DC magnetic field and the transfer magnetic field need to adopt values determined in consideration of the coercive force of the slave disk 40, the relative magnetic permeability of the master disk 46 and the slave disk 40, and the like.

  The magnetically transferred slave disk 40 can be suitably used by being incorporated in a magnetic recording device (hard disk drive). As the hard disk drive used for this, various known devices sold by each drive manufacturer may be used.

  As mentioned above, although the manufacturing method of the master disk for perpendicular magnetic transfer concerning this invention and embodiment of the perpendicular magnetic transfer method were demonstrated, this invention is not limited to the said embodiment, Various aspects can be taken.

  For example, in the present embodiment, magnetic transfer is performed to the slave disk 40 by the magnetic field generation means 30 while the slave disk 40 (also the closely attached master disk 46) is continuously rotated. It is also possible to adopt a configuration in which the magnetic field strength is reduced to a predetermined value after the magnetic field application of 1 or more in the circumferential direction is performed, and then the rotation of the slave disk 40 and the master disk 46 is stopped.

  As described above, if the magnetic field strength is gradually reduced to a predetermined value after one round of transfer in the circumferential direction and then the rotation is stopped, the influence of the transfer accuracy is very small, and the C / The N ratio becomes good.

  Further, as described above, the master disk 46 has an annular shape (doughnut shape) having an inner diameter, but may be a disk shape having no inner diameter.

  In the present embodiment, in the magnetic field generating means 30, the electromagnet device 34 is disposed above the slave disk 40 and the master disk 46. Instead, the magnet device (bar magnet) is replaced with the slave disk 40. Alternatively, a configuration may be adopted in which a magnetic field is applied on both sides of the master disk 46. Furthermore, the magnet device may be an electromagnet or a permanent magnet.

Plan view of a master disk for perpendicular magnetic transfer according to the present invention Partial enlarged perspective view showing fine uneven pattern on the surface of the master disk Cross-sectional view of substrate explaining flow of forming magnetic layer Front view of main parts of magnetic transfer device Sectional view for explaining the basic process of magnetic transfer

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Magnetic transfer apparatus, 30 ... Magnetic field production | generation means, 31 ... Gap, 32 ... Core, 33 ... Coil, 34 ... Electromagnet apparatus, 40 ... Slave disk (disk to be transferred), 40B ... Magnetic recording layer, 46 ... Master disk 46b ... servo region, 46c ... non-servo region, 47 ... substrate, 47A ... projection pattern, 47B ... depression, 48 ... magnetic layer, b ... circumferential width of projection pattern, G ... magnetic field line, l ... Radial width of projection pattern, R: resist agent, t: thickness of magnetic layer

Claims (6)

A resist agent is applied to a disk-shaped substrate having a number of fine protrusion patterns formed on the surface, the surface of the protrusion patterns is covered with the resist agent, and the resist agent is placed between the protrusion patterns. A resist coating process that substantially fills the recesses to be formed;
A resist removing step of completely removing the resist agent covering the surface of the protruding pattern by ashing, and partially removing the resist agent substantially filled in the recessed portion,
Forming a magnetic film on the surface of the substrate, forming a magnetic layer on the surface of the protruding pattern from which the resist agent has been removed, and on the recess from which the resist agent has been partially removed; and
A lift-off step of removing the resist agent applied to the recessed portion and selectively removing the magnetic layer of the recessed portion;
A method for producing a master disk for perpendicular magnetic transfer, comprising:   2. The method of manufacturing a master disk for perpendicular magnetic transfer according to claim 1, wherein a ratio t / l of a thickness t of the magnetic layer and a radial width l of the protruding pattern is 1 or more.   3. The method of manufacturing a master disk for perpendicular magnetic transfer according to claim 1, wherein a ratio t / b between a thickness t of the magnetic layer and a circumferential width b of the protruding pattern is 1 or more. A large number of fine protrusion patterns and concave portions formed between the protrusion patterns are alternately formed on the surface, and a master disk having a magnetic layer formed on the surface of the protrusion pattern and a target disk. A contact process for contacting the transfer disk;
A magnetic transfer step of providing a magnetic field generation unit, applying a magnetic field in a direction perpendicular to the surfaces of the transfer target disk and the master disk, and transferring the magnetic pattern of the master disk to the transfer target disk;
A perpendicular magnetic transfer method comprising: An adhesion step for closely adhering a perpendicular magnetic transfer master disk manufactured by the method for manufacturing a perpendicular magnetic transfer master disk according to claim 1, 2 or 3, and a transfer target disk;
A magnetic transfer step of providing a magnetic field generation unit, applying a magnetic field in a direction perpendicular to the surfaces of the transfer target disk and the master disk, and transferring the magnetic pattern of the master disk to the transfer target disk;
A perpendicular magnetic transfer method comprising: 6. The perpendicular magnetic transfer method according to claim 4, wherein magnetic transfer is performed while the transfer target disk and the master disk that are in close contact with the magnetic field generating means are moved relative to each other.

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